Supervisory control system



Dec. 8, 1931.. A. L. MOREAU 1,835,608

SUPERVISORY CONTROL SYSTEM Filed Aug. 9, 1927 5 Sheets-Sheer lWITNESSES: INVENTOR /& 5 M60 A/be/"f L. Moreau Dec.-8, 1931. A. 1..MOREAU 1,835,608

SUPERVISORY CONTROL SYSTEM Filed Aug. 9, 1927 s Sheets-Shea? 2 WITNESSESA/ber/ A -Mafieau A. MOREAU 1,835,608

SUPERVISORY CONTROL SYSTEM Dec. 8, 1931.

l iled Aug. 9, 1927 5 Sheets-Sheet 5 INVENTOR A/be/f L Mareau ATTORNEYWITNESSES:

Dec. 8, 1931. A. L. MOREAU 1,835,608

SUPERVI SORY CONTROL SYSTEM Filed Aug. 9, 1927 v 5 Sheets-Sheet 4 k m g?g WITNESSES: ENTOR g S W A/ber'l L- Moreau Patented Dec. 8, 1931 wasrArEs PATENT *pFmE j;

. ALBERT L. MOREAUQOF WILKINSBURG, PENNSYLVANIA; ASSIGNOR 'roWESTINGHOUSE ELECTRIC 8t IVIANUFAGTURING- COMPANY, A CORPORATION OFPENNSYLVANIA SUPERVISORY CONTROL SYSTEM Application filed August 9,1927. Serial No. 211,681.

My invention relates to selective signalling systems in which apparatusunits are selectively controlled and supervised from aremote station.

An object ofmy invention is to providesynchronously operated relaychains located at the two remotely disposed points for synchronouslyswitching signalling lines connecting said pointsto equivalentunits.

Another object of my invention is. to provide circuit arrangements forstepping relay chains, located at two remote points, in synchronism bymeans of a code. 1

Another object of my. inventionis. to provide means for identifying eachselected pos ition before completingthe selection. Another object of myinvention is to provide a method ofoperating a synchronous selectingsystem which includes thesteps of preparation, identification andcompletion of the selected prepared circuit.

Another object of my invention is to provide circuit arrangements forreleasin the selectors when a non-synchronous confition arises (withoutthe use of additional signalling lines).

Another object of my invention is to provide manual means forinstantaneously restoring the selecting apparatus to normal, at anytime, employing no additional signalline; lines. 7 y 1 Still anotherobject of myinvention is to provide means for employing the samesignalling line for control, supervision, drive and reset. I

Another object of my. invention is to provide circuit arrangements foroperating relay chains at two remote points in synchronism, employingonly uniform fast-type relays. l g

Another object of my invention is to provide a method of selectivesignalling which includes preparation, identification of the selection,completion of the selection and code operation of the selectedunit.

Still another object of my invention is to provide circuit arrangementswhereby the signalling are-maintained open until identification of theselection. c

There are other objects of my invention such control he held by thedispatcher indefinitely. In other signalling systems, a selecwhich,together with the foregoing, will appear in'the specification whichfollows;

The supervision and control of substation power apparatus .from adispatchers oflice in-. troduces problems not present in anyothertype ofsignalling systems. p

In most-of the existing signalling systems, a small-percentage error inselectionis usually considered permissible. No serious consequenceresults from an occasional error ina telephone, telegraph orothersignalling system. On the other. hand, in supervisory control, eachoperation is important,and the efiectmay be of serious moment. Anincorrect operation may result'in damage more costly than thesvstemitself. For this reason, it is necessary that the selectingsystememployed be infallibly accurate.

visory-control selecting systems and other selecting systems is found inthe fact that,in:

Another vital difference between superthe-former systems, itis desirableto obtain. direct control of theselected unit andthat tion is usuallymade in order to perform a single operation, such as to ringa calledparty in a telephone system. In supervisory con:

trol, on the other hand, after having selected,

an apparatus unit, such'as a circuit breaker,

further selective operations, such as opening and closing the circuitbreakermay bedesirable, and, since further selections may be performed anumber of times, it is important that the selected unit be retainedundercon-.

To accomplish 'trol-of the dispatcher until he restores the:

his latter purpose, that selecting system employs a start-stopsynchro-,-

nous operation in which the signalling lines are switched synchronouslyat the two remote I stations in a step-by -stepfashion and stopped at the'desired selected point. Direct connections of the selected unit aretherefore obtained over the signalling lines. I

In this type of synchronous selection, how

ever, the selected units are subjectedto inductive surges induced on thesignalling line.

'Heretofore, this difficulty has been corrected by interposing equipmentbetween the select- 1700 ed units and the line. This equipment, however,is both expensive and renders the system involved.

In order to overcome this difficulty, the present invention employs acode means for stepping the chains synchronously, sothat each positionis selected by the accuracy of a code, while the advantage of directconnection is obtained in that the selectors are stopped as in asynchronous start-stop system. 7 Y Y In practicing my invention, Iprovide circuit arrangements for synchronously stepping relays at tworemote points, equivalent relays at each station beingisteppedby anindividual code. Signalling lines connecting'the'two remote'points arestepped from point to point by synchronous energization' of the relaysmentioned above for sequentially connecting apparatus units at one pointto 3 their individual 0 aeratin meansat the other or remote station.Selected units are operated code combinations of impulses.

A checking circuit is provided for identifying the selections made, anda" reset is arranged to operate over the signalling line's.

"Referrin to the drawings, Figs. 1 and 2 are diagrams disclosing theapparatus and circuits at the office, and

Figs. 3 and '4 are diagrams disclosing the apn'aratusand circuits at thesubstation.

Fig. 5 is a diagram showing the order and relations of the relays asthey are energized and deenergized dur'ing'one cycle of operations. 7 Ingenerahmy invention comprises a bank ofselecting relavs'211 tof22'0,located at the ofii c'ehand bank of selecting relays 311 to.

320, located at the'substation for synchronously switching twosignalling lines 298'and 299, by means of code impulses from key to key,150 and 156', and apparatus unit to apparatus unit, 420 and 430. V i

Referring more particularly to Fig. 1,150 and 156 are individualoperating ineans. in

this case. twist-type keys. and. associated therewith are individualstop keys 151 and 157; Supervisory lamps 152. 153. 158 and 159 indicate.the condition of their individual remote apparatus unit.

position of the individual twist vkey and associated apparatus unit arenot in accord. The position of the selectors is shown by the lamps 1,55and 161. Key 167 is a master-control key which controls the supply ofenergy over-the signalling line for performing an operation following aselection. Lamps 168,170 and 171 indicate the condition of thesystem.that is, whether it is at rest or in operation and,

if in'operatiom whether in synchronism or The'relays 104 to 113 p vcontrolyrelays which functionafter a S na f v Disagreement V lamps 154and160 are illum nated when the are the operation-- tion has beencompleted for transmitting an operating code. 7

Referring now more particularly to Fig. 2, the selecting relays 211 to220 are individual to the keys 150 and 156 and are operated se-'quentially by the switching relays 201 to 210, which function totransfer the drive lineimpulses to successive selecting relays. By novelcircuit arrangements, the switching relays deenergize as soon as thenecessary switching operationshave been performed. This eliminates thedilficulties encountered when alarge numberofthese relays aresimultaneset relay operatively responsive to a nonsynchronous conditionfor restoring the selectors to normal. I

Referring more particularly to Fig. 3, selecting relays 311 to 320 areenergized sequentially in synchronism with the selecting relays 211 to220 by driving impulses received by'the driving relays 321 to331 andrelayed, in turn, to each. succeeding switching relay by relays 301 to310. Relays 332 and 333 function in response to prolonged opening ordeenergization of the drive line to restorethe relays to normal.

Referring more particularly to Fig. 4, circuit breakers 420 and 430 areillustrative of the apparatus units employed at the substation,,althoughit is to be understood'that any equipments of other types maybe theselected units;

. Relays 412to 41'? are individually 0 981110. ing relays for thecircuit breaker 420, and similar relays 422 to 427 are individual tocircuit breaker 430. The relays 402 to 409 are the operation-controlcode-receiving relays which respond to the code transmitted by therelays 104 to 113, following a selection.

Before going into a detailed description of the operation, a generaldescription of the steps which take place in making a selection will be'given. Normally, a holding circuit is completed over the control line298. The first operation, either the'closingof a key manually at theofiice or the automatic operation of a circuit breaker at thesubstation, opens the holding'circuit. -,A circuit is there- 1 uponcompleted over the drive circuit 398.

The impulse transmitted over the drive circuit is of a predeterminedpolarity and is relayed to energize the first selecting relay 211'at theolfice and relay 311 at the substation. The energization of theselecting recheck signalling line. Ii the checking imtwo stations.During this period, although! the selecting relay-s have been energized,the I supervisory and control lines 298 and 299 are open circuitedpThesupervisory line, as a. matter or :tact, functions at this timeas apulse is found to be correct, that is, a checking circuit is completed,the relay 230 energizes and completes the circuit of thecontrol andsupervisory lines 298 and 29-9 to the selecting relays atthe twostations.

A circuit is now completed from the individual key at the office overthe first selecting relay to the apparatus unit over the first selectingrelay at the substation and, if the stop key is opened, a closed ortripped code; may be transmitted for operating the circuit breaker.

In order to better understand the invert tion, a more detaileddescription of the operationwhrch now takes place wi-llbegiven. lhe

operations about to be described will best be understood if theFigure 5is, studiedat the s closes a circuit for the lamp-170 over a circuitfrom ground, armature 268 and its back con-. tact, conductor. 198,and,through the lamp 170 same time as the description-is read.

Although the relays are s'lrownconnected to apparently differentbatteries, it "will be understood that this is used for convenience inillustration and that, in actualpractice, only one battery shownthelower right hand corner of Fig. 2 is used. Thus, the relay 10-1. forexample, is connected to the negativel side of the battery shown in thelower .right- 4 for the relay 230 which by-passes the original star-tingkey 'at armature 268, the circuit behand corner of 2.; Similarly, thebatteries shown in Figs. 3 and 4 are shown for convenience inillustration and it will be 1m:

derstood that a single battery is used ipracr tice, as shown in thelower letthandcorner of Fig. 3. The positive terminals of each'of thesebatteries are connected to a common re 7 turn circuit which is thereturn. line for all of the circuits extending between thetwo sta"battery at the ofiicethrough the windingot relay 222, the back contactand armature 286', conductor 298, armature366 and its backcon= tact,through the winding of relay 330 and 7 battery, to ground. This circuit,it will be noted, is completed over the back contacts of relays .230 and322. If relay .230 is energized by the closing of a start key at theoh'ice,-or

relay 322 is energized as a result-of an automatic operation, thisholding circuit Will-be opened to start the selectors into operation bedescribed in more -de-" as will hereinafter tail.

As a resultof the energization of the relay 222 at the oft-ice, anenergizing circuit is completed for the lamp 168 from ground overarmature 268 and its front contact, conductor 196 and, through the lamp168 and battery,

to ground.- The illumination of the lamp 168.

indicates to the dispatcher that the set is at rest. The energization ofthe relay 830 at the substation prepares a start circuit for setting theapparatusinto operation, responsivetoan automatic movement of thecircuit breaker.

t will be assumed that the dispatcher desired to close thecircuit'breaker 430 at the substation. In order todo .this-he-willmomentarily operate the. start key 169 to its closed position. A circuitwill thereupon be completedfor. the relay 230 from groundthroughbattery, the win ding of the relay 230,

back contact and armature 267, conductorv 198, closed contacts of thekey 169, conductor 19?, and, through the back contact and armae ture266, to ground.

The energizationof the relay 230 at the cfliceopens the original holdingcircuit over the conductor 298 at armature 286. As a re sult of theopening of the holding circuit, the

.relay 222 at, the office and therelay 330 at the substation aredeenergized. The deenergization of the relay 222 atthe ofiice opens theoriginally traced circuit for the lamp 168 at armature .268 and its backcontact and and battery, to ground. The lamp'l68 is exsystemis startedinto operation.

A? further resultof the deenergization of relay 222 is towco'mpleteanenergizing circuit ing completed from ground through battery the relay222 at the olfice, the relay 330' at ingot the holding circuit.

With the armature 385 moved to its back p0- he substation is deenergizedupon the open- -=s iticn, an energizingcircuit is completed for g therelay 322 from ground over. armature 385 and its back contact, windingof relay 322 and. battery to ground.

lice functions to switch the control and supervisorylines *to a preparedselecting circuit of the relay at the substation likewiseTheenergization of the relay 230 the ofarmature 288 at the oliice. Theenergization."

switches the control and supervising lines to p selecting-circuits overarmatures 366 and 367 and. completes the first drive circuit over Qarmature 368. A circuit is thereupon completed from ground throughbattery back contact and armature 273, through the winding of relay 225,back contact and armature .272, armature 291 and its back contact, frontcontac and armature 288, back contact and armature 269, armature 290 andits back'contact, the ClllVG line 398, back contact and armature 365,armature 368 and its front con- .327 the substation are energized. The

energization of the drive relay at the officeletes an energizing circuitfor the first relay 211 from ground over armand its front contact,conductor 175,

back contact 121, conductor 184, and, through the winding of relay 211,to battery and ground. The circuit, it will be noted, is completedoverthe back contact of armature 121, controlled by relay 103. -As soon asthe selecting relay is energized; it prepares a circuit for thesucceeding selecting relay. In

order to prevent the succeeding relay from energizing at thistiinepitsenergizing circuit is opened at armature 121, as will be described inmore detail hereinafter.

The energization of the selecting relay 211 completes locking'circuitforitself over acircuit from ground through battery, through the winding ofrelay 211, its first extreme lefthand contact, back contact and armature236,

back contact and armature238, conductor 17 3, back contact an d armature265 to ground.

[is a result of the energization of the drive relay 327 at thesubstation, an energizing circuit 15; completed for-the first selectingrelay thereat from ground over armature 379 back contact. conductor 394,back contact and armature 434, conductor 395 and through the winding ofrelay 320 to battery and ground.

The energization of the first selecting relay 320 completes a lockingcircuit for itself from ground through battery and through the W1 n dingof relay 320 and its first contact, hack contact and armature 362, backcontact and armature 358, conductor 392, conductor contact and armature385 to 497 and back ground. 7

The first'selecting relay at the oflice and he substation are nowenergized. It will be noted that the first drive impulse was com pletedfrom negative battery at the office and over the drive line 398 topositive battery at the substation. Attention is called to this actbecause the drive impulses, it will be fonndupon further analysis,remain the same for the first four selections and then the polarity isreversed for the next four selections.

Upon the energization of the first selecting 211 at the office and theselecting relay a? its front contact, armature 382 and its 320 at thesubstation, a checkingcircuit is completed from ground through battery,the winding of relay 228, the third contact of the relay 211, backcontact and armature 270 through the winding of relay 227, armature 281andits back contact, the 4th contact of the relay 211, back contact andarmature 284, front contact and armature 287, armature 289 and its backcontact, conductor 299, back con tact and armature 364, armature 367 andits front contact, armature 370 and its back contact, the 4th contact ofthe relay 320, back contact and armature 372 and through the winding ofrelay 325, and the 3rd contact of the relay 320 to ground. This is thecheck circuit which will be completed only after the selecting relay 211at the oflice and the selecting relay 320 at the substationareenergized. If the check circuit above traced is completed, this is anindication that the correct selecting relays have been energized at theofiice and at the substation and the selection preparedkby theenergization of the relays may thereupon be completed. I

-The relay 228 in the check circuit traced above is a low-resistancerelay and fails to operate over the circuit traced. It functions to openthe check circuit to give an indicatlon at the oflice when two'succeedlng selecting relays at the same station energizesimultaneously, in which case, as will be described in more detailhereinafter, suflic ent current passes through this relay to energize1t. The

relay 227, energized in the checking circuit 7 traced above, operates tocomplete an energizing circuit for the relay 226 over the armature 280and its front contact.

The energiz'ation of the relay 226 co1npletesa locking circuit foritself from *ground through battery, winding of relay 226, frontcontact-and armature 277, and front contact and armature 275 to ground.

A further result of the energization of relay 226 is to complete anenergizing circuit for the relay 229 from ground over the armature 275and. its front contact, armature 278 and its'front contact, armature 282and its back contact, through the winding of relay 229 and battery toground.

The energization of the relay 229 switches the control and supervisorylines 298 and 299from their checking position to their operatingposition. The above-described operations, it will be noticed, take placeonly after the position of the selecting relays at the oflice and at thesubstation have been checked or identified. l

substation is. extended over the backcontact of armature 364-, frontcontact of armature 367 and 370, conductor 493, armature 437 and itsback contact, conductor 490, over the 6th contact of theselecting relay320 to con ductor 396 and armature 4630f the individual circuit breaker420,- while at] the 011106, the supervisory line 299 is extended overthe armature 289, armature 287 andits' front contact, armature 284 andits front contact,

conductor 192, the armature 124 and its back contact, back contactand'armature 125, armature 131 and its back contact, conductor 186, tothe 7 th contact ofthe selecting relay- 211, conductor 179, armature 116and its back contact, conductor 188 and through the winding of relay 232to ground. 2 r

The circuit just traced-assumes that the previous supervisory signal forthis point was the same, that is, a tripped-circuit-breaker condition.the first circuit breaker will then be defenergized, as will beexplained inmore detail hereinafter. The armature 116 will be on itsback contact. The relay 232 will not be energized, as there was 110battery in the circuit traced. 'An energizing" circuit for the lamp 153is completed from ground over armature 115 and its back contact andthrough the lamp 153 to battery and ground. Lamp 153 burns green andindicates to the dispatcher that the circuit breaker is open.

If, however, the previous supervisory signal had'been a closedsupervisory signal, the

relay 101 would have been energized and locked in a manner to bedescribed in more detail hereinafterf The supervisory signal would thenhave followed upon the opening of the circuit breaker and would havebeen completed over armature 116 and its front contact, conductor 187,and through the winding of relay 233 to battery and ground,

the first part of the circuit being the same as that traced above.

The energiz'ation of the relay 233 would have provided a shunt circuitfor the locking battery of relay 101 from ground over ,armature 294 andits back contact, front contact and armature 296, the last contact ofthe selecting relay 211, conductor 178 and through the armature 114 tobattery and ground. As a result of this circuit, the lockof relay 323,back contact and The relay 101 individual toingcircuit of relay. wouldopened and relay 101 would have becoine deenergized; to complete theabove-traced circuitforthe lamp 153, indicating to thedis' patcher thatthe circuitbreaker has opened,

Referring now again tothe selecting operations, a further result oftheenergization of the relay 229, following the correct checkimpulsetransmission, is to. complete an en-. 1

vidual to this point has not beenoperated. Not only is this-circuitcompleted over the contact of the key, but also over the :front contactsof the check relay and selecting relay; The relay,= therefore, must I be'enere gized, that is, a selection must have been. made before thisoperation which isprepara tory to the succeeding selection, can becompleted. Ifthe stop key has been operated to its open position, thestepping operations tracedthus farwill stop, and no further selecting;relays willbe energizeduntil the stop key is again releasedto close itscontact at 151. a

I, The energization of the relay 223' completes a locking;- circuit foritself from ground through battery, winding. of, relay 223, -frontfcontact and armature 271, and over the conductorl89-to ground over thecircuit traced above.

course, upon the fact that thestop 'keyindi deenergizes and opens theoriginale'nergizi ing circuit of the relay 226 at armature 280. Theenergization of the relay 223 also opens the drive circuit at armature272 andthereby deenergizes the drive relay 225.

Attention is called, at this time, to the fact that control andsupervisory operations take place while the drive circuit is energized,and the preparation for the stepping operations takesplace by theopening and furthe-rclosing of the drive circuit during a non-operatingcontrol and supervisory period. This is an important feature of thissystem, since,

maintaining the drive circuit energized during the operating period, itbecomeslpossible to detect non-synchronous conditions 7 and restoretheapparatus to normal without the needof'further signalling lines.

The above-mentioned detection and restoration become possible by reasonof the fact that, at no time, should the drive, line be opened for avery long period of time, since it is only opened momentarily during thestepping periods. If the apparatus is brought .to a stop forany'operating purposes, the drive line is closed. Wherefore, ifthe driveline opens for a period longer than a predetermined reasonable steppingtime, it is due to some difficulty or trouble in the system and thisextra long open period can then be employed to automatically reset theapparatus to normal.

If, on the other hand,trouble should occurwhen' the driveline is closed,it is only necessary for the dispatcher to open the drive line and keeit open for an interval of time, whereupon the apparatus is restored tonormal; This will be described in more detail hereinafter.

The above description of the operation has now been traced through acomplete cycle. lVith the drive line opened at armature 272,

the relay 225 at the ofiice and 327 at the sub-' station aredeenergized. The deenergization of the relay 225 at the oilice completesan energizing circuit for the first switchover relay 201 from groundthrough battery, winding of relay 201, thesecond'contact ofselecting-relay 211, and back contact and armature 274 to ground.

The'energization of the relay 201 completes a locking circuit for itselffrom ground through battery, winding of the relay 201, front contact andarmature 236, back contact and armature 238, and back contact andarmature 265 to ground.

A further result of the energization of relay 201' is to complete anenergizing circuit for the relay 103 from ground through bat tery,winding of relay 103, conductor 174,

"' front contact and armature 235, and back contact and armature 265 toground. 7

The energization of the relay 103 completes a locking circuit for itselffrom ground through battery, the winding of relay 103,

front contact and armature 120, conductor 7 173 and back contact andarmature 265 to ground.

' The energization 'of the relay 103 opens the original energizingcircuit for the first selecting relay 211 at armature 121 and completesan energizing circuit for the relay 164 over armature 122 and its frontcontact.

The energized relay 164 completes a looking circuit for itself overarmature 166 and "the key 162 and completes a circuit for the buzzer 163over armature 165. The dispatcher is thus advised that the set has beenstarted into operation. Should he be away from his desk when the set isstarted into operation,

due to an automatic movement of a circuit breaker, his attention is thuscalled to the fact that a change has taken place, and he willimmediately return to his desk to find out what operation has takenplace. The buzzer "continues until he operates the key 162 in order toopen the locking circuit of therelay The energization of the relay 201switches the selecting relay circuit from the drive recircuit for theswitchover relay 310 from 1 ground through battery, winding of relay310, second contact of the relay 320 and back contact and armature 379to ground.

The relay 310 locks itself over a circuit from ground through battery,winding of relay 310, front contact and armature 362, back contact andarmature 358, conductor 392, conductor 497 and back contact and armature385 to ground.

The energization of the relay 310 completes an energizing circuit forthe relay 401 from ground through battery, winding of relay 401,conductor 393, front contact and armature 361, conductor 392, conductor497 and back contact and armature 385 to ground. The energization of therelay 401 completes a locking circuit for itself over armature 432 andconductor 497, as traced above.

The energization of the'relay 401 opens the original energizing circuitfor the first selecting relay 320 at armature 434 and transfers thestarting circuits of all the apparatus units to the reset relay 410overthe front contact of armature 433, as will be described in moredetail hereinafter.

The energization of the relay 310 opens the locking circuit of theselecting relay 320 at armature 362 and its back contact and pre paresan energizing circuit for the next selecting relay 319 at armature 363and its front contact.

Returning now to the operations at the ofiice, a further result of thedeenergization of the drive relay 225 at the office is to open thelocking circuit for the relay 226 and the energizing circuit for therelay 229 at armature 275. The signalling lines are now restored totheir original positions for first transmitting a check impulse.

Upon the deenergization of the selecting relay 211, the locking circuitof the relay 223 is opened at its fifth contact. The deenergization ofthe relay 223 again completes an energizing circuit over the drive linefor the relay 225 at the ofiice and relay 327 at the substation,the'circuit being completed from battery at the office to ground at thesubstation.

Upon the energization of the relay 225 at the ofiice, an energizingcircuit is completed for the second selecting relay 212 over a circuitfrom ground through armature 274 and its front contact, the frontcontact and armature 237 and through the winding of relay 7 contact andarmature 241and back contact and armature 265 to ground.

At the substation, the e'nergizationof the drive relay 327 completesanenergi'zingcircuit for the second selecting relay 319 over a circuitfrom ground through armature 379 and its front contact, armature 382 andits back contact, front contact and armature 363 and throughthewindingof relay 319 to battery and ground. 7

With the second selecting relay at the ofiice and that at the substationenergized, a check circuit will be completed from ground over the thirdcontact of the selecting relay 212, the back contact and armature 270through the winding of relay 227, armature 281 and its back contact,thefourth contact of the selecting relay 212, back contactand armature284, front contact and'armat'ure. 287, armature 289 and its backcontact, conductor 299 and back contact and armature 864, armature 367and its'front' Contact, armature 370 and its back contact, fourthcontact of'the selecting relay 319, back contact and arma ture 372,through the winding of relay 325,

the third contact of the selecting relay 319 and through the winding ofrelay 324 to battery and ground. g

It will be noted from the above that each selecting relay, uponenergiz'ation, prepares a circuit for its individual switchover mceeding selecting relay. By this arrange-V ment, a positive opening ofthe previously completed connection of, the control and supervisorylines over the first selecting relay is accomplished before it is.possible to complete a circuit through thefsucceeding selecting relay. 2

As further protection against possibly making incorrect selections, thecontrol and supervisory line, it will be noted, are maintaineddisconnected from the selecting relays during each stepping operationand are not again completed until the checlrimpulseim dicates that theselection has been correctly and properly made, i p It will be notedthat the second drive impulse was of the samepolarity and over the sameline, and, therefore, identical with the first drive impulse.-Therefore, it is quite possible that the wrong selecting relay may beenergized. However, the check impulse just traced is completed throughthe contacts of the two selecting relays at the oflicc and at thesubstation and is of the opposite polarity fromthe check impulse tracedabove for the first selecting relay. The combination of the-check anddrive impulses areincrating positions. 1(l6IltlCLl to those descrlbed'in connection dividual for each pair of equivalent selecting relays atthe oifice and at the substation. That is, for eachselecting position, adrive and check impulse of a predetermined polarity and over apredetermined. line individual to thatiselecting position is completed.

If relay #1 at theofiice and selecting relay #2 at the substation wereto be energized,

this check impulse would not be completed. It will be noted that thecheck impulses are completed over' the third and fourth contacts ofthevarious selecting relays. A study offthe disclosure will show thatthe third contact of the first selecting relay at the oifice isconnected to the winding of relay 228 and battery, whereas the th rdcontact of thefirst selecting relay at the substation isconnected hasenergy from battery at the ofiice to employed to distinguish the variouscheck,

impulses, but also achange in the signalling line over which the impulseis to be transmitted. The check impulse traced above not onlypassesthrough the third contactof the selecting relay but also throughthe fourth.

While the third contact, as explained above,

determines the polarity which is tobe'transmitted, the fourth contactdetermines the line over which this impulse shall be transmitted.

In the case of the first two selecting relays, since the polarity isreversed, as indicate, above, there is no needto change-the signallingline, and the fourth contacts of the two selecting relays are multipledand connected over the supervisory line. i

If the check impulse traced above is properly completed by reason Ofthecorrect en: 'ergizatlon of theselecting relays at the ofiice and at thesubstation, the check relay 227 is energized. Theenergization of therelay 227 completes an energizing circuit for the relay 226'over thearmature 280.

The energization of the relay 226 completes a locking circuit for itselfover armatures 277 and 275 and, at the same time, an energizing circuitis completed for the relay 2279, as described above.

The energization of the relay 229 switches the control and supervisoryline to their op- These operations. are

with the-first selecting-relay operation;

Similarly, at the substation, the energization of the relay;825 over thecheck circuit traced above completes an energizing circuit to, ground.The checkimpulse, therefore,

I CO

tions.

for the relay 326 over the circuit traced above, and the energization ofthe relay 326, in

turn, completes an energizing circuit for the relay 323, as tracedabove.

The energization of the relay switches the control and supervisory lines298 and 299 from their checking to their operating posi- The control andsupervisory circuits are now again completed.

If the stop key has not been pulled out at the second selectionposit-ion, the drive circuit is again opened, the signalling lines areagain switched to their check positions and the drive line thereuponagain closed for the third drive impulse; This impulse is identical withthat traced for the first two. When, however, the third selecting relayis ener-. gized, the check impulse transmitted is completed from groundthrough the battery, the winding of relay 228, the third contact of therelay 213, back contact and armature 270, the winding of the relay 227,armature 281 and its back contact, the fourth contact ofthe' relay 213,back contact and armature 283, the

front contact and armature 286, over the con the same polarity.However,'it will be noted that this impulse is transmitted over adifferent conductor. This particular check cir-' cuit can only becompleted if the third selecting relay at the ofiice and the thirdselecting relay at the substation are energized. Should selecting relay#3 at the office and relay #4 at the substation, or any othernon-equivalent combination of selection relays be energized,

this circuit would not be completed. If the check impulse is correct,the energy transmitted will operate the relays at the office and at thesubstation for switching the signalling lines to their operatingpositions, as has been described in detail above.

When the fourth stopover relay 205- energizes, an energizing circuit iscompleted for the relay 224 over a circuit from ground through battery,the winding of the relay 224,front contact and armature 247, and backcontact and armature 265 to ground. .The energization of the relay 224reverses the connection of the winding of the relay 225 from battery toground at armature 273 and its front contact.

At the substatiom'upon the cnergization of the fourth selecting relay,an energizing circuit is completed for the relay 328 from ground throughbattery, winding of the relay 328, front contactand armature 352,conductor 392, conductor 497, and back contact and armature 385 toground. I

fice and relay 328 at the substation, as described above, reverses thepolarity of the drive impulse from battery at the oiiice and ground atthe substation to battery at the substation and ground at the oflice. Itwill be noted that the first four selecting relays are energized bydrive impulses of the same polarity. Each selection, however, isidentified or checked by an impulse, individual to that selection,either by a different polarity or by a different transmission line. Thusit may be said that each selecting relay has been operated by a code,since two impulses, both of which must be of the correct polarity andover the correct line, are transmitted before a selection was completed.

The selecting relays from 5 to 8 are now energized in the mannerdescribed above in connection with the first four selecting relaysexcept that the polarity of the drive impulse is reversed. At eachenergization of a selecting relay, a check impulse is transmitted inexactly the same manner as described in detail above to identify theselection either by polarity or signalling lines over'which the impulseis transmitted.

Upon the energization of the eighth switch over relay 208 at the otfice,the energizing circuit for the switchover relay 224 is opened atarmature 256. Similarly, the energization of the eighth switchover relayat the substation opens the energizing circuit of the relay 328.

The deenergization of the relay 224 at the oiiice and relay 328 at thesubstation restores the drive circuit to its original condition, and theninth and tenth selecting relays are energized by drive impulses whichare like those which energized selecting relays 1 to 4.

A further result of the energization of the eighth selectingrelay is tocomplete an energizing circuit for the relay 231, from ground throughbattery, the winding of the relay 231, the front contact and armature256, the back contact and armature 265 to ground.

At the substation, the energization of the eighth selecting relay 303completes an energizing circuit for the relay 321 from ground throughbattery, Winding of the relay 321, the front contact and armature 340,conductor 392, conductor 497, and backcontact and armature 385 toground.

The energization of the relays 231 and 321functions to transfer orswitchover the conductors 299 and 398. The drive impulse, it will berecalled, was transmitted overthe conductor 398. As a result, however,of the above-described switching operation, conductor 398 will nowfunction for the ninth and tenth selection as the supervisory line andconductor 299 which formerly functioned as a supervisory line, now isthe drive line.

The next drive impulses, while ofthe same polarity as those whichenergized the first four selecting relays, will" nowbe transmitted overthe conductor 299 and over the front contact of armatures 290 and 365tothe line drive relays 225 and 327, as traced be fore.

The check impulse for the ninth and tenth selecting relays 'Will betransmitted over the conductor 398. Asis clear from the .abovedescription, no two selecting relays have the same combination. Thiscode canbe con tinned by employing the conductor 398- as the supervisoryline and theconductor 299 as the drive 111116 for the next eightselecting relays, whereupon, thecontrol line can be switched withthed'rlve line nrthesame man- I ner as described 1n detail above, sothatthe:

drive impulses are transmitted over the conductor 298, and theconductor- 398. functions: 7

This codingcan be conkey 150 to position the keyfor closing thecircuitbreaker. I

As a result of the" operation of stop key 151, the circuitformerlytraced through the stop key for energizing the relay 223 in,

order to open the drive circuitis not completed at. this time, andthedrive circuit. remains closed, thereby stopping thelrelay T ductor195,.contact of thefmasterkey167, conchain from further stepping,

. Thedispatcher will now-operate the ter key 167 to its closed position.and main tain it in this position until the correct supervisory signal,indicating that the circuit breaker has closed in accordance with hisoperations, is received.

Should the dispatcher open the master key before the signal; isreceived, the apparatus is restored to normal ithout performing theoperation, as will be described in more d e;

tail hereinafter.

After the selection has been made, acode of impulses is transmitted overthe line+operatingchain of relays, both at the ofiiceand at thesubstation, for closing the circuit A difierent code is employed fortripping the circuit breaker. This arrangement for operating the circuitbreaker as breaker.

a selector by means of a codeis called operation control.

It is an essential part of a supervisorycontrol system inasmuch as itovercomes one of the chief difficulties experienced in employ ing asynchronous relaygsystem, namely, the sensitiveness of such a system toelect-rlcal disturbances from extraneous sources.

It is, of course, possible to so operate synchronous system that-as theline shall be switched synchronously at both ends, di-

rect circuits are completed. at .each position" to apparatus unitswithout. the use of a fur-r 'ther code ofimpulsesxforactual,operation. 1

upon the apparatus units, since it requires. not. I

only that a completeand correct selection, bemadefor'opera'ting'the'unit but-also the. transmission of the. proper;code thereafter. In this case=,.fiveiimpulses, three over the controlline and two over the supervisory line, for .changingthe polarity are.transmittedfor: closing the selected circuit breakenwvhile threeimpulses; are transmitted for trippingv the ,circuitbreaker; 1 1Therelays 104 t0 113, are the operationcontroll relays located; at theoffice, and the relays. 402 to 409;. the relays located at thesubstation for receiving operation-control code signals. g i.

The code that is tobe transmitted is determined. by the particular.relay 107 or 105 energizeds 'Energization of the relay 107' causes thetransmission of five impulses for closing. the circuit breaker, and theenergization of the relay 105 transmit's three impulses;

for .tripping' a circuit, breaker. 7

In this instance, since it isassumed that the circuit breaker is to beclosed, theindividual key has been operated to energize the relay; 1'07over-a. circuitlfrom ground through bat.-

tery, the winding'of1relay.107,fthe closed contact of the key' 150,conductor .180, the sixth. contact of "the selecting relay 211,conductor 194C,"arn1ature,2 76 and itsfront contact,back contact andarmature 279 and the In front contact and armature 275t0 ground."

It'will be noted that this circuit. is completed over the'front contactof the line-driverelay 225. The circuit is Ialsocompleted over the frontcontact of-thecheck relay 226. This LI.

completes an ena V contact andilower armature of relay 113, frontcontact andarmatu're 132 andover con-v Y ductor 194 to ground as tracedabove. I

yyTh'e jenergization of the relay'226 -completed the first? operationcontrol impulse over the control line from. positive batteryat thevolfice to negative battery at the substation, the circuit beingcompletedfrom ground over the fifthcontact'of the selectingrelay 1211,conductor 181, the right-hand contact of the stop .key 151, the armature136 and'xits back contact, back contact. and-arma-. Y

ture 139, the upper contact of the key. 167,. conductor 193,. the frontcontact and arma-:

ture 283, front contact and armature 286, conductor 298, armature 366,and its front tact and battery to ground.

The energization ofthe relay 406 at thesubs'tation completes anenergizing circuit for therelay 404 from ground through battery,windingof the relay 404, front contact and armature 446, conductor 495,armature 374 and its back contact, front contact and arm'a-.

ture 382, front contact and armature 379 to ground The relay 404, whichisa slowrelease relay, energizes and remains closed during thesucceeding periods of impulses.

A further result of the energization of the V an energizing circuit foritself over the front relay 406 is to complete an energizing circuit forthe relays 402 from'ground through battery, winding of the relay 402,back contact and armature-449, front contact and arma-' ture 447, frontcontact and armature 442, and over conductor 495 to ground, as tracedabove. I

Theenergization of the relay 402 completes'an energizing circuit overthe super visory line from positive battery at the substation tonegativebattery at the office. This circuit is completed from groundover the conductor 495, armature 442 and its front cont act, armature448 and its back contact,

armature 454 audits back contact, front contact and armature 437,conductor 493, front contact and armature 370, front contact'andarmature 367, armature 364 and its back contact, supervisory line 299,back contact and armature 289, armature 287 and'its front contact,armature 284 and its front contact, conductor 192, armature 124 and itsfront contact, through the winding of the. relay 108, armature 140 andits back contact, to battery and ground. a y

The energization of the relay 108'at the office completes an energizingcircuit for the relay 109 from ground-through battery, winding of relay109, back contact and armature 142,- front contact and armature 133,

" front contact and armature 132 to ground oyer'the conductor 194. Y Y

The energization of the relay 109 opens the originally traced impulsecircuit over the.

control line at armature 136. The opening of the controlline'deenergizes the relay 406 at the substation which, in turn,completes an energizing circuit for the relay 407 from ground throughbattery, winding of relay 407, back contact and armature 439, frontcontact and armature 436, back contact and armature 447, front contactand armature 442 to ground over the" conductor 495, as traced above, andalso completes an energizing circuit for relay 405 from ground throughbattery winding of relay 405', front contact and armature of relay'404,back contact and armature 446 to ground over conductori495;

The energizationof the relay 407 at the substation opens the originallytraced supervisory impulse at armature 448 and completes a lockingcircuit for itself over this armature from ground through battery,winding of the relay 407, front contact and armature 448, front contactand armature 442 to ground over the conductor 495. The opening. of thesupervisory line deenergizes the relay 108 at the office which, in turn,completes an energizing circuit for the relay 111 from ground throughbattery, winding of the relay 111, back'contact and armature 146, backcontact and armature 134, and front contact and armature 137 to groundas traced above. i

The energization of the relay 111 completes pletes the third operationcontrol impulse over the control line'from negative battery at theofiice to positive battery at the substation, the circuit beingcompleted from ground through battery, armature 144 and its backcontact, front contact and armature 139, upper contact of the master key167, conductor 193, front contact and armature 283, front contact andarmature 286, conductor 298, armature 366 and its front contact,armature 369 and its frontcontact, conductor 494', and through thewinding of relay 406, armature 450 and'its front contact to ground overconductor 495.

The energization of the relay 406 co1npletes an energizing circuit forthe relay 403 from ground through battery, winding of the relay 403,back contact and armature'453, front contact and armature 449, frontcontact and armature 447, front contact'and z grgiature 442 to groundover the conductor substation completesa locking circuit for itself fromground through battery, winding'of the relay 403, front contact andarmature 438, front contact and armature 442 The energization of therelay 403 at the visory line from negative battery at the substation topositive battery at the office, this circuit being completed fromthrough the battery, armature 443 and its front contact, armature 440and its front contact, armature 445'and its front contact, armature 451and its back contact, armature 454 and its back contact, front contactand :J 9

ground a:

tor1 2, the front contact and'armature 124,

and through the winding of the relay 108, armature 140 and its frontcontact, back contact and armature of the relay 106 to ground overconductor 194. r. I

fThe energization :of the relay 108 com plates an energizing circ uitfor the relay 112 from ground through .battery,:-Windingof. the relay112, front contact and armature 142, front contact and armature 133xtoground, as traced above. 7 1..

The energization ofthe. re'lay1l2 completes and energizing circuit foritself over the front contact and armature 145. The energization of therelay 112 opens the third operating control impulse. over'the controlline at ar1nature144.. As aresult, the relay. 406 is doenergized at thesubstation and completes an energizing circuit for the relay 408 fromground through battery, Winding of the relay 408, front contact andarmature 439,

front contact and armature 436, back con tact and armature 447, frontcontact and armature 442 to ground-over the conductor 49,5.

The energization of the relay 408 completes a locking circuitffor itselfover the front contact and armature .452 and over t contact and armature442lto ground 0'. erthe conductor 49.5. l A further result of theonergization of the relay 408 is to open the fourth operation Icontrolimpulse over the SHPGLVlSOLy line at armature 451 and to prepare anenergizing circuit for the relay 409 at'armature 453. 7

The opening of the supervisory line at the substation deenergizes therelay 108 at the oliice- The deenergization of the relay 108 at theoffice coinple es'an energizing circuit forthe, relay 113 over, thecircuit from" ground through battery, Winding of the relay 113, frontcontactand armature 146, back contact and armature 134, and frontcontact and armature 137 to ground over the circuit traced above.

The energization of the relay .113-com" pletes a locking circuit overthe armature 149 and its front contact. A further resultof theenergization of the relay 113 is to complete the fifth operation controlimpulse from negative battery at the office over the control line toround at the substation I a u o b 7 this circuit bein com leted fromround A O e through battery, 'thearmature 148 and: its

front Contact, front contact'and armature 139, the upper contact of themaster key 167, conductor 193, front contact and armature 283, frontcontactand armature 286,

conductor 298, armature, 366 and its front contactf-arniature369 and itsfront contact conductor494, through the Winding of the.

relay 406, arniatl'ire 450 and lts front contact, :to ground overitheconductor 495;

The-energization of the relay 406 at the substation completes anenergizing, circuit for the'relay 409 from ground through batt'ery,Winding of the relay: 409, front contact and armature 453,- frontcontact and armature 449, front contact and armature 447, front contactand armature 442 to ground over thef-conductor-495'. y

A furtherresnlt of the energization of the relay 406-is to. open theenergizing circuit of-the relay 405.

.'-After an interval oftiine, the armature of relay, 40 5 :drops to itsback position. A circuit is thereuponcompleted for closing the circuitfrom'ground through battery, armature 443 and its front contact,armature 440 and its front contact, armature 445 and its backcontact,armature.455 and its front contact, conductor 491, the seventhcontact of the selecting relay 320, conductor 397 and through theWinding of the relay 414 to ground; i g

Theenergizat'ion of the relay 414 completes ane'nergizing circuit forthe solenoid 417 from thene ative side of thebattery, front contactandarmature .466, winding of the solenoid 417'to, positiviesideof thebattery, the

energization of the solenoid 417 completing an obvious energizingcircuit for the operatingmagnet 419 over the contacts 472 and 473. Thecircuit breaker 420 is thereupon operated to itsclosed position. Theclosing of the circuit breaker completes an obvious energizing circuitfor the relay 413 which, upon energization, in, turn, completes anenergizing circuit for the relay 412 over arn1ature 485.

- The energization .of'the relay 412 operates its arinature .463andcompletes an energizing circuit over the supervisory line from groundthrough battery, front contact and armature 463, conductor 396, sixthcontact of selector relay320,-conductor 490, back contact and armature437, conductor 493, front'contact and armature 370, front contact andarmature367, armaturef364 and its back contact,

supervisory line 299, back contact and armat l T 289, armature287andlits front contact, armature 284 and its front contact,conducrelay211, conductor 17 9, armature. 116 and its back. contact,conductor 188 through the Winding of the relay 232 to ground. 7

The energization of the relay 232.con1plefes i an energizing circuitforthe relay 101 from ground through battery, armature 295 and its frontcontact, back contact and armature 296, eighth contact of the selectingrelay 211,

conductor 17 8 through the Winding of th relay 101toground;v z

fore, happen that he closes the circuit breaker The energization of therelay 101 completes a locking circuit for itself over armature 114 andopens the circuit for the lamp 153 at the back contactof 115 and-at itsfront contact closes a circuit for the'lamp 154.

The extinguishing of the lamp 153 and the illumination of the lamp154thusqgives an indication to the dispatcher that the circuit breaker has closed in accordance with his operation. I

Since the circuit which the dispatcher is to close is, remotely disposedfrom him, he has no Way of ascertaining the condition of the lineat thetime he operates the circuit breaker to the closedposition. Itmaythere'- on a short-circuit. In such case,the overload relay on thecircuit breaker will immediately operate to'trip the circuit breaker toits open position. This may happen while the control impulse is stillcompleted for the operate winding of the circuit breaker so that thecircuit breaker will again start. to close,

' followed, of course, by an immediate opening thereof when it closesupon the short-circuit.

This may happen a number of times, causing what has become known in theart as pumping. consequences, not only to the circuit breaker but to theline which is thusbeing periodically closed. It is essential, therefore,to provide some means whereby, if the circuit breaker once closes and isimmediately opened, it may not close again unless the dispatcher goesthrough the operation of tripping the circuit breaker and then againclosingit by the operation of his keys.

This problem becomes difirlcult by "reason of the'fact that the palletcontacts of the circui U breaker are so arranged that the supervisorysignals may be completed before the circuit breaker has completed itsentire movement and been latched closed. A 7 Means must be provided formaintaining the energy on the line a predeterminedlength of time inorder to insure that sufficienten ergy' is suppliedto completely closethe circuit breaker. A s-a part of this means, it'is further necessarytoprovide an arrangement for disconnecting this source of energy in casethe circuit breaker latch isclosed and then tripped.

Iprovide a simple and very accurate antinumping arrangement. It Wlll beassumed that, immediately upon the closing of the cir tion, after ashort interval; of time, and-a circuit is completed over the'supervisoryline Pumping may result in serious of the back contact the relay 101being energizedat this time, conductor 187 relay 233 tobattery. v i

The energization of the relay 233 completes a shunt circuit for therelay 101 from ground over the armature 294 and its back contact, frontcontact and armature 296, eighth contact of the selecting relay 211,conductor 178 over the armature 114 and its front contact and batterytoground. The relay 101 isthus deenergizedand permits the armature todrop to its back position,

The lamp 154 is extinguished and the lamp 153 illuminated, therebyindicating to the dispatcher that the circuit breaker has been tripped;A further result of the energizetion of the relay 233 is to open theenergizing circuit of the relay 110. It will be re called that thiscircuit was completed over the conductor 191 and armature 297. 7

Upon the energization of the relay 233, this circuit is opened atarmature 297. The deenergization of relay opens the control line atarmature 139. The opening'of the control line deenergizes the relay 406at the substation. The deene 'ization of the relay 406 opens theenergizing circuit for the relay 404 at I armature 445.

, 111, 112 and 113 still remain energized so long as the master key isdepressed so that no new open tion can be restarted, since the controlline is opened at relay 109 at the office.

Under-these conditions, in case the master key is released, the relay107 will still remain energized over a circuit from ground throughbattery,;winding of the relay 107, the closed contact of the key150,-conductor 180, sixth contact of selector relay 211, conductor 195,front contact an d armature 1 0, armature 138 and its back contact,front contact and ari'z'iature 147, conductor 194, armature 276 and itsfront contact, back contact and armature 279,

and front contact and armature 275 to ground. r 4. 1

In 01 der, therefore, to release the appara tus under, these conditions,it is necessary,

not only to open the master key 167, but also to switch the twist key toits tripped position in order that it may agree with the condition ofthe circuit breaker.

The circuit for the relay 107 is, thereupon, deenergized which, in turn,opens the circuit for the relays 108, 109, 111 and 113, all of whichhave been energized over the front contacts ofarmature 132 of the relay107.

Upon the restoring of the stop Ikey '151'to close its left-handcontact,an energizing circuit is completed for therelay 223, as traced above,which opens the'driveline'at armature 272, and the apparatus isthereupon stepped again-from contact to'contact. I

Upon the energization of the last selecting relay 220, an energizingcircuit is completed for the relay 221 from ground through bat tery,winding ofthe relay221, armature 264 and its front contact, and front:contactand armature 274 to'ground. The energization of the relay221-opens the round circuits of all the locking andenergized relaysatarmature265 'and 266: All

' of the relays are-deenergized, and a locking circuit is completedforthe' r'elay221 from the ground to battery, winding of'the relay.

221, front contact and ar1nature- 267, back contact and armature 268".toground;

At the substation, upon the energization of the last selecting relay,the" energized clrcuit of all the locked relays "is opened and theapparatus is restored to normal-in thesame manner. for the relay 222' atthe office and the relay 330 at the substation, as originally "traced.

- The energization of the relay-222at the sub;

station opens'the energizing circuit" of the relay 221 which thereuponis deenergized to its original normal position.

In the foregoing, the. manner in which a circuit breaker is operatedto aclosed position by the transmission-of-five'impulses has been described.InQorder to operate the breaker to a trip position'instead of to aclosed position, only three impulses are trans,- mitted as stated above;This is accomplished by operating the twist key 150 to the positionshown, whereupon a circuit is completed for the relay instead of for therelay 107, the circuit extending from ground throughbats tery to thewinding of relay105, through the left hand contact shown closedv in{thekey 150, and thence over; conductor 180 as traced above inconnection. with the relay. 107.. It will be noted that relay 106 isconnected in multiple with-relay 105 andenergized'simultaneouslytherewith.

As a result of the energization ofrelay 105,

a circuit is completedfor the relay 104 from tion to energize relay 402as a result of which second control A circuit is'thereupon completed {1the secondcontrolimpulse was. transmittedfrom thesubstation totheoiiice- Thissecond impulse, it willbe recalled, energized relay 7 108,which, in-turn, energized relayil09l 'En-.

ergizationof relay 109 opened the energizing circuit, of the firstcontrol impulse, deenergizing relay 406. Relay 406 upon deenergiza'stion energized relays 407 and 405. Energiza tion of relay 407uopened thecircuit for the impulse circuit, to deenergize the relay 108.Energization of relay 10.8 onergizes'relay 111. which,.in turn,energizes relay '110'and upon energizationofrelay 110,

the third controlimpulse is transmitted over the lineto energize relay406.. Relay 406, upon energization, energizes 'relayf 403 which preparesan energizing circuit for the :relay 108-as describ edin full above.This operation is repeated up to this point for'tripping the bl' eiker.L

.It will be noted at this time, however, result of the energization ofrelay-106, the

circuit. for the fourth control-impulse which energized relay I 108,, isopened atv the back contact of the first armature of energized-remainsenergized for ailonger period of time than normal-and,- during. thisperiod the relay 405, which as described here, isgenerl gizedover theback contact and armature 446, 15 deenergized after an interval of, timeand drops its-armature445 to its back contact,

completing thereover acircuit for, performing. an operation. I

1 In the first described operation for closing he breaker,-following thetransmission of the five controlimpulseathe relay 409 was energizedbefore the relay 405 deenergizedand accordingly the operating circuitwas completed over .thearmature 455; and its front I 106, softhat-nocircuit' can be completed 7 for this: fourth control impulse.Accordingly, "the relay 406Jat: the remote station. re-' Contact whichas traced out over conductor 491, 'eXtends to the relay 414.

In the present case, however, inasmuchas only three impulses weretransmitted before the pause occurred. permitting the deenergizationofthe relayr405, relay 409 has not been energizediandaccordingly thecontrol circuit rendered effective when relay 405 deenergizes, extendsover the ar-matures 455 and its back contact and through.thecontactsofthe selecting relay to relay 415 which, in

turn, complete an energizing circuit for the solenoid 415 to complete anenergizing circuit for the tripping magnet 418.

" Aswill now be clear' from the above de' Y scription, the'closing isperformedbyfive impulses'during which periodthe relay405 is maintainedenergized, it being a' slow-re lease relay whlchremalns energized duringthe short intervalsbetwe'en the energization V of relay 406. When'the{impulsing stops, however, and the relay406 remains energized for longerthan a predetermined interval, a

sufiicient time is provided for permitting deenergization of relay405and, as a result,the control circuit iscompleted. The control 7 circuit,inturn, dependsupon-whether the relay 409 has or has not been energized;if

only three impulses have been transmitted as describedaboVe,.thel-relay409 is. not men gized. 1 In order to. restore theapparatus to normal, it is necessary to. operate the stop key 7 'aresultof the operation of the stop key to its normal-position,therelay406iis deenergized',

whichdeenergizes any of the operation'con trol relays at the substationsuch as relays 402, 403, 404, 405, 406, "407; In'this manner the eiitireapparatus is restored to normal.

Should a circuit breaker. automatically operate, the-apparatus is setintooperation in substantially the same manneras that de scribed inconnection with azkey operation. Inorderto illustrate this, it Will beassumed that the circuitbreaker 420 is automaticallyclosed.- Upon theclosing of .the circuit breaker an energizin g circuit is completed forthe rel'ay 413 1Vhich, in turn, completes ant-energizing circuitforthe'relay 412...

1 'Following the energization of therelay 413, but before the relay 412'is completely energized, :a circuit is completed for the relay 410 fromground over armature 464-and this purpose.

its ffront contact,b'ack contact and armature 462, armature433 and itsback contact, con;

ductor 497-and through'the Winding of the 1 relay 322 and battery toground.

The 'energization of the relay 322 opens the normal holding {circuitover the control line 298 and -deene'rgizes the relays 330'atthesubstation and 222 at the office. Thereafter, tlie' drive circuitoperates in exactly the manner described above in connection Witlianoperation from the office until the "circuit breaker which'ha's beenoperate'd'is'reached, whereupon a supervisory signal is transmittedover'the supervisory line, in am'ane .d scri d bo ee j 7 It may happenthat a second circuitbreaker will be operatedautomatically after theircuitfbreaker 420 has operated but before the apparatus has beenrestored normal. Means must. be provided for preventing the supervisorysignal for this operation from beinglost. A restart circuit is providedfor It will be recalled that one of the first re 7 lays Which energizedupon' operation of the first selecting relay is the relay 401. .The

energization of the relay 401 transfers the start'operati'on previouslytraced over the armature. 433 and its'back contacttoarmature 433 and itsfront contact.

It Willbe assumed that the circuit breaker 430. closes Whilethe selectedrelays are in operation and the relay 401 is energized and locked overarmature 432. As in the case of the circuit breaker 420, upon theclosing of the circuit breaker 430, the relay423 is energized and, :inturn, completes an energizing circuit forthe relay 422. Before theand-armature 458 to ground over the con ductor498. -A further resultofthe energization of the relay 410 is to prepare an energizing circuitfor the relay 411 over the armature 456; This circuit is not completedat thistime because, during the operation of the selecting relay, therelay 330'is deenergize'dzand the armature 385 is: on its back contact.r

.After the selecting relays have completed their cycle of operation andbeen restored to normal, in the manner described in detail above, therelay 330 is energized. A circuit is-thereupon completed. from groundover armature 385 and its front contact, conductor 496, front contactand armature 456 and through the Winding ofthe relay 411 and batterytoground.

The energization of the relay 411 completes a locking circuit for itselfover armature 459 and its front contact to ground over conductor 496,and the armature 460 completes a circuit for the'relay' 322 overarmature 457- anditsback contact. This'momentary circuit energizestherelay 322, Which, thereupon, again starts the selecting apparatus intooperation, in the manner described in detail above. e

A further result of the energization of the relay 411 is to open the.energizing circuit of the relay 410 at armature 461'. The relay 410 isdeenergized and, in turn, completes a circuit for the relay 322 over theconductor- 497. The relay 322 isenergized and starts the selectedapparatus into operation, in a manner described in detail above.

. As soon as the apparatus is started into operation,-'t he relay 330 isdeenergized and opens the lockingcircuit of the relay 411; Therelay 411is deenergized to open the original energizing circuit of the :relay322. The selecting apparatus now operates in the manner described aboveuntil the circuit breaker which is operated is reached, whereupon a ill)nssaeos supervisory signal is transmitted, in the man-v ner described indetail above. 1 i i This arrangement also provides a repeat circuitwhich operates everytime anapparatus unit is changed to check thecircuitof'the unit for the dispatcher. Thus, should the dis patcherselect any circuit breaker foroperation and complete the operation ofthe breaker, the supervisory signal is received, the selecting apparatuscontinues through until finally restored to normal, whereupon the cycleof operationsis again repeated andfa second supervisory signal or checkispro vided for the dispatcher. r 2

it will be recalledjthat it was-pointed out, inthe beginning of thespecification, that, if the relays fallout of step, so that two non.-synchronous sele'cting'check relays are energized simultaneously, thecheck circuit will fail to operate. A further arrangement has beenprovided for immediately restoring the apparatus to normal should suchaiconditio'n.

occur. a I, r

In order toillustrate the operation, it will be assumed that theselecting vrelay 211at the oiiice energized.simultaneously ywithftheselecting relay 319 at the substation. As has been pointed out in detailabove, no checking circuit is completed, and the relay 227, therefore,fails to be energized. The lamp 171 which is energized every timeltherelay-227 is energized, fails to illuminate and the .dispatcher is thusapprized of trouble .in his set.

In order to restore the apparatus to normal, it is only. necessary forhim toclose'tlie key 172. An obvious energizing circuit is.

thereupon completed for the relay 234i. The energization of relay 234.efl'ectsthe opening of its armature 291 to open the drive circuit andarmature 292 to remove the shunt circuit.

around the highresistance 292a to insertthe resistance in the energizingcircuit for the relays 222 and 330 which are energized when the systemis in a normal non-operating condition.

At the same time armature 2926 opens the negative side of the stationbattery circuit for all the normally non-energized relays at thedispatchers office. In other words, the armature 2925 controls or opensa bus conductor which is illustrated simply as a batteryand groundconnection at each relay throughout the system. V

Therefore, it is evident that theopening'of armature 292?), ofrelay-23l, restores allthe relays at the dispatchers oliiceto theirnormal condition. w y Since the normal operating; condition is attainedwhen the drive lineis ClOSGdytllQ drive line is normally open onlyforsmall intervals of time duringv the operation of the selectingrelays, namely, periods during switching from one selecting relay, tothe succeeding selecting relay.- The energization of the relay 2345,however, maintains thedrive circuit for the relay the *relay'333 isnormally maintained energized overfthe frontcontact of armature 380 whenthe system is in operation. Durlng the line open at armature 291 for aperiod longer than 18 usual during the operating condition.

short interval of time betweenthe stepping operationsywhile the relay327 is deenergized, relay cannot be'cleenergizedy since it isfaslow-releaserelay.

Upon the opening of thedrive line, however,- and'its benig mai'ntainedopen for a longperiod'oftime, the relay 333 drops to its back positionand completes an energizing over the armature 391.- The energization'ofthe relay 332' eflects the opening of its-armature 332a toopen thegroundcircuit of all the energized relays at the substation which are,thereupon, restored tonormal. E 1 3. As described hereinbefore, theopening of armature 292, of'relay 23 i, inserted the high resistance292a in the energizing circuit for relays 222 and 3 30. .Thiscauses'relays and 330 to drop out if they are energized or toremain outof deener 'ized, and relay 33O at itsyarmature 385a opens the normalholding circuit for maintaining relay333 closed when the'driverelay 327is not operating. This permits the: relay 333 to open its-arn'iature391, when the armature 380 of the drive relay 327v remainsfopen for aprolonged inter val of time in response to the operation of key 172.., II

f two selecting relays at either'the oliice or stat-ion, are operatedsimultaneously, the apparatus is restored'to normal in the followingmanner. It will be assumed that resimultaneouslyl A circuit is thereuponcompleted for the relay 228 from ground through battery windingof'the'rclay 228, third con? tact of the relay 211, and third contactofthe relay 2l2toground.

The energization offthe relay 228 opens the circuit ofthe checlrrelay227 at armature 281. The dispatcher is thus apprised of trouble in thisapparatus. The relay 22S,

. 0 lays 21-1 and 212 at the ofiice areenergized it should'be noted, isso designed that, when energizedin series with the relay .227, asis trueduring the checking operations, it does not get enough energy .tooperate its armature, but,when locally energized, as traced above, itoperates its armatures to their front contacts.- Similar y,'theenergization of any two selecting relays at the substation willcompletean energizing circuit for the relay The energization of therelay 324 opens the circuits otthe relays 323 and325 to restore theapparatus to'n'ormal, in the manner described in detail above. Falseoperations of any kind are thus-eliminated..-

